1. Field of the Invention
The present invention relates to a communicating apparatus and, more particularly, to an apparatus which can communicate either one of or both of an image and a voice.
2. Related Background Art
Hitherto, as an example of such a communicating apparatus, a television telephone system using a telephone line has been known. In such a system, in the case of transmitting an image, an analog image signal is converted into a digital signal, the digital signal is first stored into a digital memory, the stored digital data is modulated into a signal in a frequency band of 300 to 3400 Hz of the telephone line, and the modulated signal is transmitted as the analog signal. On the other hand, in the case of reception, the received analog signal is demodulated and converted into digital image data and stored into the digital memory, a stored image data is converted into, for instance, a television signal, and the TV signal is supplied to a TV monitor apparatus. On the other hand, when the transmission and reception of image data are not executed, communication by a voice signal is performed in a manner similar to a conventional telephone.
With respect to such a television telephone, a function similar to the absence recording function in a conventional telephone receiving only the voice signal is demanded. In the telephone receiving only the voice signal, for instance, a message upon absence reception is recorded into a semiconductor memory or on a magnetic tape and a message from the distant side is recorded into the semiconductor memory or onto the magnetic tape. On the other hand, in a telephone using a personal code number, only when the personal code number has been received from the outside are the recorded messages are reproduced and transmitted.
However, in the case of merely storing messages into the memory, only the voice can be transmitted and no image can be transmitted.
On the other hand, with respect to the received image, if the received image is merely stored into the digital memory, the preceding stored image will be erased by the reception of the next image. On the other hand, in the case of recording the received image onto the magnetic tape or the like, in order to check whether the received image has been recorded or not, the image is first demodulated and stored into the digital memory and read out and displayed by a TV monitor, while the voice signal must be reproduced from the magnetic tape on which the voice signal was recorded. Thus, it takes a long time and the operations become complicated.
It is a large problem as to which one of the reproduced image and the received image is preferentially output to the monitor in the case where a (voice or video) signal is received from the telephone line while the recorded image signal is reproduced and checked in the absence recording mode.